chemistry 40F unit 5: redox

oxidation

atom loses one or more electrons, becoming more positive as a product than as a reactant

reduction

atom gains one or more electrons, becoming more negative as a product than as a reactant

LEO GER

lose e- oxidation, reduction gain e-

oxidation number

represents the charge the atom would have if every bond were ionic
- not every bond is ionic, but chemists assume they are for this system.
- the oxidation number is not always the actual charge, but it is very helpful to follow electrons in redox reactions

are oxidation numbers always assigned per atom?

yes

what is the oxidation numbers of all uncombined elements (just one element no others)

0

what is the oxidation number of monatomic ions (1 atom with a charge)

equals the charge of that ion

in compounds what is the oxidation number for alkali metals (G1)

always +1

in compounds what is the oxidation number for alkaline earth metals (G2)

+2

In compounds what is the oxidation number of aluminiums

always +3

in compounds, what is the oxidation number of flourine

-1

in compounds what is the oxidation number of hydrogen

+1

exceptions to hydrogens oxidation number in compounds always being +1

in metal hydrides, like NaH or MgH2, where hydrogen is -1

in compounds, the oxidation number of oxygen is what

-2

what is an expection to the oxidation number of oxygen always being +2 in compounds

peroxides, like H2O2 or Na2O2, where the oxidation number is -1

for any neutral compound, what must the sum of the oxidation numbers be equal to?

0

for any polyatomic ion, what must the sum of the oxidation numbers for each atom be

must be the charge of that ion